"People were saying, 'They can get bronze,' then 'they can get silver,' then 'they can get gold!" said Emile Smith, an executive at the centre. "It echoed through the building."

Gold it was, leaving South Africa in a pleasant state of disbelief. In the Beijing Olympics the team won a paltry silver medal; in London it has three golds already. The lightweight men's four followed swimmers Cameron van der Burgh winning the 100m breaststroke in world record time and Chad le Clos edging out Michael Phelps in the 200m butterfly.

Perhaps South Africa's biggest cheerleader is the sports minister, Fikile Mbalula. An official statement released on his behalf was almost incoherent with excitement: "We don't want to sound like a broken record, what welcomed us in Britain, has phenomenon, victory was certain. We are proud of the four young men, who made our flag to rise above all and our national anthem to be sang louder."

The rowers' success was the top story on national TV news. Matthew Brittain, Sizwe Ndlovu, John Smith and James Thompson came from behind to snatch the title from favourites Britain and Denmark. Ndlovu, 31, South Africa's sole black winner in London so far, is a former police reservist who worked for the Pretoria flying squad, according to sports journalist Neal Collins's blog.

Born in Johannesburg, Ndlovu was inspired to take up rowing in 1997 by his headteacher. "He was actually the one who saw the potential in me and encouraged me to row," he told the Sport 24 website. "He used to pick me up in the mornings at 5am, make me train before classes, then go to school and also train in the afternoons. That was Tom Price, what a great man. He passed away in 2006."

The team has six-hour training sessions three times a day. The team members are struggling to balance their sporting careers, which yield little financial reward, with studying or work.

South Africa is no sporting minnow and recently toasted Ernie Els' victory in the Open and its cricketers' first Test thrashing of England. But the country has never before won Olympic gold in rowing or male individual swimming.

Smith of the high performance centre, which also coached van der Burgh, said government intervention had led to more specialisation and concentration on training. "There's been a progressive element in South African sport. The 2010 football World Cup provided an impetus," he said. South Africa's team is also smaller than it was in Beijing and may be more focused.

Sports journalist Carlos Amato added that this time: "The resources have been concentrated on medal contenders."

The victories would boost national morale, he added. "It matters hugely. It's funny how we take it more seriously than we should. To have a multi-racial rowing team winning gold really matters. It's sentimental but it's true."

This being South Africa, race matters too. Amato said: "There's been large black interest and celebration of the success of the white athletes. But the team is still way too white. You saw that in the opening ceremony which wasn't very different from the first team that was readmitted to the Olympics in 1992. A lot of Olympic disciplines are still for the elite who have access to facilities and resources."

Runners Oscar Pistorius and Caster Semenya are still to come and, perhaps one day, a bid to host the Olympics. Following Rio in 2016, Africa will be the only continent still waiting its turn.